1. Field of the Invention
The present invention generally relates to MIMO (multi input multi output) mobile communications systems, and more particularly relates to weighting factor reporting methods in MIMO, and base stations and user apparatuses that are suitable for use in the methods.
2. Description of the Related Art
A multiple input and multiple output (MIMO) communications scheme is known which uses multiple antennas between a base station and a user apparatus. In this scheme, a directional beam may be utilized which is formed by multiplying multiple streams, generated by duplicating a signal stream to be transmitted, with weighting factors corresponding to the streams, making it possible to improve transmission speed and quality of a transmission signal. The weighting factor used here is called a pre-encoding vector or a pre-encoding matrix.